The Program Project focuses on the role of CRF superfamily peptides and their binding proteins, receptors and modulators in the integration of endocrine, autonomic behavioral and immune responses to stress. The first aim of this Program is to characterize physical interactions between CRF family ligands, their receptors and binding proteins and to define motifs required to activate downstream signaling events. The second aim is to explore the physiologic and pathophysiologic significance of these molecules at the cellular and system levels and to study the control of protein expression and secretion as well as modes of action. Physiologic and pharmacologic studies proposed by the Projects in this Program are critically dependent upon our ability to measure relevant hormones in a variety of biological fluids. Core B will provide RIAs of CRF superfamily peptides, pituitary hormones and glucocorticoids. The Core is responsible for ensuring quality control of these assays.